Polymorphism is common in solid drugs, and drug compounds in different crystalline forms have different physical and chemical properties. Polymorphism is one of important factors that have influence on the effect and quality of solid drugs. Different crystalline forms may differ by several times in solubility, and also differ greatly in in vivo distribution and metabolism, causing differences in bioavailability. In addition, solid APIs (active pharmaceutical ingredients) in different crystalline forms and preparations thereof show different stabilities during preparation and storage process, which would cause crystalline transformation and thus influence the quality of the drugs. Therefore, the polymorphism would finally influence the quality, therapeutic effect and safety of solid drugs.
5α-androstane-3β,5,6β-triol is one of polyhydroxy steroids, and has significant neuroprotective effect. The study on its polymorphism is very important for further studying its efficacy, bioavailability and stability. X-ray single crystal diffractometer, X-ray powder diffractometer and differential thermal analyzer are main tools for quantitatively determining the specific type of polymorphism, which provides more qualitative and quantitative information for the study on crystalline form of solid drugs.